Process for producing improved asphalts



caws an. A26a/Duyn /mer l v H. E. cir-:R vPRocEss Fon PRoDUcING lmrnovnAPHALTs l y 3 Shts-Sxeet 1* y Filed D ec. 19, 1940 Fior N y ou. aufm IMEtcPANl A. .STA/PPAA/ Patented Nov. 24, 1942 i I l g e l UNITED STATESPATENT OFFICE PROCESS Fort PRODUCING iMPRovED AsPnALTs e Harry E. Cier,Baytown, Tex., assignor to Standard Oil Development Company, acorporation ofl Delaware Application December 19, 1940, Serial No.370,774 s claims. (ci. 19evii This invention relates to a process forproduc- `The relationship existing between the penetraing improvedasphalts and more particularly, the tion and softening point may beexpressed by the invention is concerned with the production of equation1 n asphalts having improved susceptibilities to tem- M=7tPape'iiizurireiaerlilyeniasrs different ,gi'adeseof4 asphalts Ymere M isthe Ieg and bau softening point in have been prepared by blendingasphalts of low del" P'ee peneatlen and falnd k eielgonses penetrationwith naphthas, gas oils, and heavier tepen nlg en e seuree e e asp. a.an k e fluxing agents. In fact, it is customary practice elerauetet.Whleh .the peeeelretmn l. te lele in the asphalt industry to prepareintermediate w existil g1 tvyenmfx 1S atrm arte?? @ning grades ofasphalts by inuxing a natural or oxis b 1% F31 1e Y etpen 27513232' Idized asphalt with a suitable blend stock to prouy e 15.0. .vlseesl y et measures duce an asphalt of proper specifications. It is e suseeplblhty ofthe asphalt te eonelsteney also well known in the art to dilutea crude changes et .elevated tempelfaturee Whereas ehe residuum with aliquefied normally gaseous 5 seftenmg pemt'penetratleeleeex 1s an.mdleetlen hydrocarbon and, by proper adjustment of term of thetemperature susceptibility of an asphalt at perature, to throw out orprecipitate from the oil nelgeal temera'uresg'z. F') '1 t y solution anasphalt which is suitable, after ux- 1s an e Jee. ef 1S meen len o prouee en ing with a lighter oil or` asphalt, for use in road asphalt thatWm net eeftee te a great degree when used as a filler in either wood orstone zo f building or in manufacture of other material for blockpavement. An *asphalt that Win soften which asphalt has been adapted'under normal summer conditions and which will Propane precipitatedasphalts when blended to Deze out of. the jointsronto the paving blocksis f designation D5-25. The softening point, by the 'flgcormy rllltgggglcltfg; nndesirabie and ,ebieetionabid It is a 'further and uxmg methodit is possible to produce a 5 obiect of this invention to produce anasphalt wide range of products However these conventhat While neem netsoften and eV under-usual tionally produced asphalts frequently have ahigh Lbellemcllgsleeielrt lggdmerasuz' softening peint'penetration indexand a reletvely `mixtures and in road urfaciig compolitilon ggvrldlgrllgals gclaggl E'igl gierl 30 where it is necessary that the aggregatebe coated with binder to produce a coherent adhesive` mass.

point-penetration and fluidity indexes, since one It has now beendiscovered that if a crude re index indicates the consistency at normaltemperatures Whereas the other index is a measure .sldlm 1511 medgth eheavy O11 flletlen end of consistency at elevated temperatures.` In 1Sen d1 u e W1 propane.' en .esp en of. 1m' Short these indexes forasphalt may be Compared 35 proved temperature susceptibilitycharacteristics to the viscosity index for lube oils. The softenlgebamgtggg lglrf ttlat ephellts ing point-penetration and iluidityindexes aredep 5ft t. g t1 1 .p 1er e p .0' scribed by Holmes, Collins and Child(Measur pane preelpl e' len are Vas y Supener le quality ing thesusceptibility of asphalt to temperature to asphalts proqud by propanepreclpfatlon changes H01mes Collins and Child, mi & Eng* do followedbyuxmg. For asphalts of equivalent Chemistry Analytical Edition, vol.8-pages 100- penetratlon thls product produced m the man' 104 Marcil 151936) who arbitrarily assigned a ner Which will be further described indetail, has Vahle of 100 for asphalts from Mexican crude and highersusceptibility vindexes than are obtained either by conventional propaneprecipitation or 0 for asphalts from cracking coil tar.

The softening pointmenetmtion indexs a re1a .n by conventional propaneprecipitation followed tionship existing Vbetween the penetration of anby uxirng- In general this invention H lay be deasphalt at '77 F. andthe ring and ball softening SCllbed' as fOllOWSt a crude pe'rOleum isreduced point. The method ef test for determining the by dstlllalpn t0 aresldwm hai/mg a mmimum penetration of an asphalt is described in the1939 Saybolt UnlVerSal VSCOSIY 0f about 400 Seconds Book of A. s. T. M.standardsincluding Tenta- 5f) at 210 F. While it is preferred to reducethe tive standards, Part, 111, under the A, S T, M crude to what istermed in the art a short residuum, 4it may also be reduced to alongrering and ball method, is also described in the siduum. After reducingthe crude to the miniaforementioned reference under A. S. T. M.desigmumy viscosity required the residual Crude may nation E28-39T. beuxedwth a lubricating oil fraction which fractions which will allowprecipitation of asphalt from solutions thereof may be employed. Thepropane-oil solution is cooled to a temperature where asphalt andresinous material will precipitate and is then introduced into asuitable settling drum where asphaltic and resinous material separatefrom the solution as a bottom layer. The asphalt is drawn olf from thesoluble oil and propane layer, may be washed with additionalamounts ofpropane, and is then stripped of residual solvent. The solvent-freeasphalt is then suitable for use in road building or otherwise as may bedesired.

' In the accompanying drawings, Figure 1 represents a general ow diagramof the process; Figure 2v a softening point-penetration graph; andFigure 3 a furol viscosity-penetration graph. With reference to Figure 1which represents a now diagram of one embodiment of this invention, aheavy lubricating oil flux is introduced through line 2 into line Ithrough which a crude oil residuum fraction is being charged by means ofa pump not shown. The two oils are thoroughly mixed in incorporator 3and are then heated to between about 120 F'. to 180 F. in heating means4. The heated fluxed residuum is then diluted withV liquid propane whichis introduced through lilies I9 and 20; make-up propane, when needed,

may be injected into the system through line I8. The fluxed oil andpropane are thoroughly mixed in incorporator 5 and the temperature ofthe resulting propane-oil solution is adjusted to about 110 F. to 150 F.in heat exchanger 6 from whence the mixture flows into asphalt seti tler1 which is preferably maintained at a temperature of about 110 to 130 F.However, the temperature of the asphalt in the settler may be maintainedeither higher or lower than the limits mentioned since the penetrationof the precipitated asphalt is controlled by the precipitationtemperature in the asphalt settler. An oilypropane solution is drawn offof settler 1 by means of line 8 into propane stripper 9 where solventand lubricating oil are recovered. Vaporized propane from stripper 9 isreturned to the system through line I0, liquecation means I2, and lineI9. Deasphalted lubricating oil is drawn olf of the bottom of stripper 9through line Il to storage. Asphalt is drawn olf of the bottom ofsettler 1, through line I3, into propane Stripper I4 where the asphaltis stripped of residual propane, the propane stripped from the asphaltbeing recycled to the charge system by means of line I5, liquecationmeans I1, and line 20. Asphalt of improved quality is drawn off tostorage from the bottom of stripper I4 through line I6.

Although the mechanism of the solvent action, resulting in theimprovement in asphalt temperature susceptibilities, Wrought by fluxingof postulated that by fiuxing the crude residuum prior to propaneprecipitation, poor fractionation between the predominantly oily and thepredominantly asphaltic constituents occurs. This is a desirable ratherthan an undesirable condition, since it is further theorized that theundesirable components in the oil or asphalt employed as a uxing medium,which normally impart poor susceptibility t0 the mixture, are dissolvedin the solvent, whereas those components which contribute toward goodsusceptibility are included with the precipitated asphalt. Thus, ineiect according to these theories, the ratio of oils to resins in theasphalt produced in accordance with this invention has been increasedover that contained in asphalt produced by conventional propane.precipitation followed by uxing. It is to be clearly understood,however, that this invention is not to be limited by any theories whichmay be advanced in explanation of the improved result.

In order to more clearly describe this invention, reference is made tothe following examples:

Example 1 Asample of' crude oil from the Pearsall field in Texas wasreduced by distillation to 34.3%

bottoms. 'I'his residual fraction from the crude had the followingcharacteristics:

Specific gravity at F 1.005 Open cup flash, F 610 Furol viscosity at 275F 91 Pen. at77 F., 100 g.,.5 sec 232 Ring and ball softening point, F104 Ductility at 77 F'. 110+ Solubility in C014 99.69 Oliensis testNegative The 34.3% bottoms fraction having the above inspectioncharacteristics was subjected to a series of deasphalting treats inwhich one volume of reduced crude to four volumes of propane of 96%minimum. purity was employed. Temperatures between 120 F.. and 140 F'.were employed in the treats. The asphalt obtained from these treats weretested and the following inspection data were obtained:

Treat l Treat 2 Treat 3 Deasphaltng temp., F 120 130 140 Asphalt yield,Ywt. por cent on charge-- 69. 6 70. 4 82. G Specific gravity at 60 F1.050 l. 025 1.034 Open cup flash, F 615 620 G15 Furol viscosity at 275F 381 280 101 Pen. at 77 F., 100 gms., 5 sec 32 41 60 Ring 'and ballsoftening point, F-. 135 128 122 Ducniipy ai 77 F 110+ 11o-I 110+Solubility 1n C014, per cent 09. 57 99. 73 99. 74 Oliensis test Neg Neg.N cg.

The sample of Pearsall crude residuum representing 34.3% bottoms on theoriginal crude was then fluxed with a fraction from the same cruderepresenting a 42-65.'7% fraction. The blended residual fractionrepresenting 58% bottoms on the.- crude had the following inspectioncharacteristics:

Specic gravity at '77 F 0.958 Open cup ash, F 385 Furol viscosity at 122F 572 Per cent asphalt of penetration '74.8

'I'he fluxed bottoms fraction having the abovedescribed physicalcharacteristics was also subjected to a series of deasphalting treats inwhich one volume offluxed reduced crude to four volumes of propane wasemployed. The propane diluent ranged between 87.4 and 96% by volumeminimum purity. Distillation analyses rof the propane diluent showed theyimpurities to consist mainly of ethane and a small quantity of butanes.Thus for example, the analysis of the 87.4% propane diluent was asfollows: Ethane 12.4%, propane 87.4%, butanes 0.2%. atures between 120F. and 140 F. were employed in the propane precipitation of asphalt. Theasphalts obtained from the treats of the iiuxed residual fraction weretested and were found to have the followmg charactenstics: l

Treat 4 Treat 5 Treat 6 Treat 7 Treat 8 Deasphalting temp., F 120 140120 130 140 Asphalt yield, wt. per

cent based on charge 40. 5 46. 0 38. 5 39. 5 45. 5 Specific gravity at60 F. 1.035 1. 019- 1. 042 1. 033 1. 041 Open cup flash, "F 425 425 420425 430 Furol viscosity at 275 F. 339 127 320 269 222 Pen. at 77 F., 100gms.,

5 SBC 48 165 41 66 77 Ring and ball softening 2 point, F 13o 1u 133 126123 0 Ductility at 77 F 110+ 110+ 110+ 110+ 110+ Solubility in C014, per

cent 99. 75 99. 74 99. 67 99. 62 Olicnsis test Neg. Neg. Neg Neg. Neg.

Temper- 5 Child, fluidity indexes for asphalts having 50, 100, 150, and200 penetration were obtained.

Fluidity index 9 C Ashalti f, onvenpro uce Irenetratlon at77 F. tonauyin accord produced ance with asphalt this (treats 1-3) invention (treats4-8) On comparing the physical properties, as measured by softeningpoint-penetration and fluidity indexes, of asphalt produced inaccordance with this invention with that produced by conventionalpropane precipitation, it is readily apparent that this improved processproduces asphalts of greatly improved temperature susceptibilitycharacteristics.

` Example 2 It will be noted on comparing the data obtained on theasphalt from treat 2 with that from treat 6 that, for an equivalentpenetration, the flash on the asphalt obtained in treat 6 is 200 F.lower than that obtained in treat 2 indicating that this asphaltcontains lighter material than the asphalt from treat 2. It is thislighter material which imparts the desired temperature susceptibilityqualities which are readily apparent from a further study of the data.

The softening point and penetration data obtained in treats 1 to 7 werethen plotted on 2 cycle logarithmic graph paper with the ordinaterepresenting the ring and ball" softening point and the abscissarepresenting penetration at 77 F. These data are presented graphicallyin Fig- Softening pointpenetration index Asphalt Penetration at 77 F.Convenproduced tionally in accordproduced ance with asphalt this (treats1-3) invention (treats 4-8) 62 89 80 11o fc5 85 130 100 150+ In asimilar manner, the furol viscosity of the asphalts from the severalaforementioned treats were plotted as ordinates on logarithmic graphpaper against penetration at 77 F. as the abscissa. These data arepresented graphically in Figure 3. Then by recourse to the Fluidityindex chart also constructed by Holmes, Collins, and 7A A residualfraction representing 34.3% bottoms on Pearsall crude was deasphalted at120 F. employing four volumes of propane to one volume of the bottomsfraction. The resulting asphalt, which corresponds to that obtained intreat 1 shown in Example 1, was then uxed with a light motor oil toproduce asphalts of different penetrations.

Blend 1 Blend 2 Blend 3 Asphalt, wt. percent 100 95 92. 5 Light motoroil, wt. percent. 5 7. 5 Furol viscosity at 275 F-.. 381 229 182 Pen. at77 F., 100 gms, 5 sec 32 57 72 Ringand ball softening point, F. 135 125121 The softening point and penetration data. obtained on inspections ofthe blends was then plotted on logarithmic graph paper and are Soteningpoint-penc tration index Asphalt produced by propane precipitation andAsphalt produced in accordance with this invention Penetration at 77 F.

On comparing the data in Example 1 with the `above results it will benoted that identical values were obtained by conventional propaneprecipitation and by propane precipitation followed by iiuxing. 'I'heasphalts produced in accordance with this invention, i. propaneprecipitation, however, are superior in temperature susceptibility (asmeasured by the softening point-penetration index) to either of the twoconventional methods. Similar advantages are shown for asphalts obtainedby my ime., fluxing followed byV proved method Whenuidity indexes arecompared.

Example 3 A residual fraction representing 34.3% bottoms on Pearsallcrude was blended with equal volumes of a light motor oil. Inspectioncharacteristics of the Pearsall bottoms fraction are shown in Example 1.The light motor oil Was tested and had the following characteristics:

Specific gravity 0. 8783 Open cup ash, "F 450 Open cup fire, "F 530 SSUviscosity at 210 F 50. 3

Asphalt Asphalt precipitated precipitated at 120 F. at 140 F.

Furol viscosity at 275.o F 924 574 Peu. at 77F., 10() gms., 5 scc.. 1728 Ring and ball softening point, F. 153 142 Open cupflash,F 520 525These data were then plotted on Figures 2 and 3 to which reference hasbeen made. The softening points were plotted as ordinates and thepenetrations as abscissae on Figure 2. It Will be noted that these datafollow the curve plotted from the data on asphalt obtained from treats 4to 8 in Example 1.

In a similar manner, the furol viscosities at 275 F. Were plottedagainst penetrations on.

Figure 3. It will again be noted that the data follow the curve for theasphalts precipitated in treats 4 to 8 rather than the curve forasphalts from treats 1 to 3 presented in Example 1.

These data demonstrate that asphalts of superior temperaturesusceptibility may be produced in accordance with this invention offluxing the residuum prior to propane precipitation rather thanafterwards. The data also clearly show that the ux need not be avcontiguous fraction of the same crude from which the asphalt isobtained. This is important since it may be desirable in some instancesto flux the residual fraction with a low grade product for which noready market exists.

I claim:

1. Process for producing asphalts having improved susceptibilitycharacteristics to temperature changes comprising the steps of uxing areduced crude with a loW viscosity hydrocarbon fraction boiling Withinthe lubricating oil range, diluting with a liquefied gaseoushydrocarbon, adjusting the temperature so that an asphalt isprecipitated therefrom, separating said precipitated asphalt from thatportion soluble in the diluent and stripping said precipitated asphaltfree of light hydrocarbons.

2. Process for producing asphalts having improved susceptibilitycharacteristics to temperature changes comprising the steps of iiuxing areduced crude with a low viscosity hydrocarbon fraction boiling Withinthe lubricating oil range, diluting said iiuxed reduced crude fractionwith a liquefied normally gaseous hydrocarbon, adjusting the temperatureof said diluted, uXed reduced crude fraction so that an asphalt isprecipitated therefrom, separating said precipitated asphalt from thatportion of the uxed reduced crude fraction soluble in the diluent,freeing said separated asphalt of entrained oil fractions by Washingsame with additional quantities of liqueed normally gaseous hydrocarbonsolvent, stripping said washed asphalt free of light hydrocarbons in astripping still, and recovering therefrom an asphalt of improvedtemperature susceptibility characteristics.

3. Process in accordance with claim 2 in which the liquefied normallygaseous hydrocarbon is propane.

4. Process in accordance with claim 2 in which the fluxing agent isblended with the residual crude fraction in the ratio of 0.2-2.5 volumesof uX to one volume of residual crude fraction.

5. Process in accordance With claim 2 in which the fluxing agent is anunfinished lubricating oil fraction.

6. Process for producing asphalt having improved susceptibilitycharacteristics to temperature changes Which comprises the step ofreducing a crude to a minimum Saybolt Universal viscosity of about 400seconds at 210 fiuxing the reduced crude with a low viscosityhydrocarbon fraction boiling Within the lubricating oil range, dilutingWith a liqueiied gaseous hydrocarbon, adjusting the temperature so thatan asphalt is precipitated therefrom, separating said precipitatedasphalt from that portion soluble in the diluent and stripping saidprecipitated asphalt free of light hydrocarbons.

7. Process of producing asphalt having improved susceptibilitycharacteristics to temperature changes Which comprises the steps ofreducing the crude to a minimum Saybolt Universal viscosity of about 400seconds at 210 F., fluxing the reduced crude With a low viscosityhydrocarf bon fraction of the same crude boiling within the lubricatingoil range, diluting with a liqueed gaseous hydrocarbon, adjusting thetemperature so that an asphalt is precipitated therefrom, separatingsaid precipitated asphalt from that portion soluble in the diluent andstripping said precipitated asphalt free of light hydrocarbons.

8. Process of producing asphalt having improved susceptibilitycharacteristics to temperature changes which comprises the steps ofreducing by distillation an asphaltic crude to a residuum having aminimum Saybolt Universal viscosity of about 400 seconds at 210 F.,uxing the residuum with a low viscosity hydrocarbon of a diierent crudeboiling Within the lubricating oil range, diluting said fluXed reducedresiduum with a liquefied normally gaseous hydrocarbon, adjusting thetemperature so that an asphalt is precipitated therefrom, separatingsaid precipitated asphalt from that portion soluble in the diluent andstripping said precipitated asphalt free of light hydrocarbons.

HARRY E. CIER.

